Known also as beta- adrenergic blocking agents, beta blockers are medications that are given for angina pain, hypertension (high blood pressure), heart attacks, heart failures, heart arrhythmias, and sometimes for glaucoma and other disorders. These drugs work by blocking epinephrine and norepinephrine from binding with adrenergic beta receptors belonging to the sympathetic nervous system. By blocking epinephrine and norepinephrine, the receptors of the heart muscles, arteries, kidneys, airways, and other parts, the ill effects of the stress hormones are reduced considerably. Beta blockers of three types – Beta-1, Beta-2, & Beta-3. By blocking the receptors of epinephrine and norepinephrine of beta-1 and beta-2 receptors, the heart rate reduces, and the blood pressure also reduces. There is also considerable dilation of blood vessels. Beta blockers also have the effect of blocking and obstructing a hormone produced in the kidneys called angiotensin II. This further assists in the reduction of blood pressure. Beta blockers come in two types. Some of them are selective and some of them are nonselective. While the selective beta blockers are prescribed for their pronounced effects on the heart, nonselective beta blockers are prescribed for their action on the heart, and their capacity to block receptors of both adrenaline and noradrenaline. People who are prescribed beta blockers have to be careful about its interactions with antidepressants, antidiabetic medications, and medications for COPD, bronchitis, and asthma. Some side effects of beta blockers include fatigue, drowsiness, dizziness, stomach disturbances, constipation or diarrhea, headache, shortness of breath, trouble sleeping, confusion, sore throat, and back pain. Beta blockers are known to worsen diabetes control. By reducing the heart rate, the patient cannot realize hypoglycemia symptoms earlier and they block the release of insulin thus causing high blood sugars.